Gibbs Free Energy
Mostrando 25-36 de 105 artigos, teses e dissertações.
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25. Spectroscopy analyses of polyurethane/polyaniline IPN using computational simulation (Amber, MM+ and PM3 method)
The polyurethane (PU)/polyaniline (PANI) IPN, at three composition ratios (95/05, 75/25, 60/40), were analyzed, after the action of the urease enzyme, by means of the Hyperchem 8v software. Theoretical analysis of Gibbs free energy, FTIR, and 13C-NMR were done. The generation of functional groups due to hydrolysis was analyzed by FTIR. The 13C-NMR spectra of
Polímeros. Publicado em: 2014-08
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26. Propriedades relacionadas à acidez e basicidade a partir da abordagem em química computacional
Analytical Chemistry books lack a clear link between thermodynamic and equilibrium approaches involving acids and bases. In this work, theoretical calculations were performed to search for these relations. An excellent relationship was found between difference in Gibbs free energy, ∆G of acid dissociation reaction and ∆G of hydrolysis reaction of the cor
Quím. Nova. Publicado em: 2014
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27. Kinetic, thermodynamic properties, and optimization of barley hydration
The hydration kinetics of five barley cultivars was studied at six different temperatures ranging from 10 to 35 ºC for 32 hours applying the Peleg model. Response Surface was used to describe dynamic of the process and identify the hydration time for each cultivar. The activation energy (Ea), enthalpy (ΔH*), entropy (ΔS*), and Gibbs free energy (ΔG*) wer
Food Sci. Technol. Publicado em: 2013-12
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28. Application of computational chemistry methods to obtain thermodynamic data for hydrogen production from liquefied petroleum gas
The objective of this study was to estimate thermodynamic data, such as standard enthalpy, entropy and Gibbs free energy changes of reaction and, consequently, chemical equilibrium constants, for a reaction system describing the hydrogen production from Liquefied Petroleum Gas (LPG). The acquisition of those properties was made using computational chemistry
Braz. J. Chem. Eng.. Publicado em: 2013-03
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29. Análise termodinâmica de processos de reforma do metano e da síntese Fischer-Tropsch / Thermodynamic analysis of methane reforming processes and Fischer-Tropsch synthesis
The reactions of reforming of light hydrocarbons, especially natural gas, are chemical reactions of great importance and represent key steps for large scale production of hydrogen for use in hydrogenation reactions or fuel cells, or synthesis gas production, for application in the ammonia or methanol production, or to Fischer-Tropsch (FT) synthesis. The Fisc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/03/2012
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30. Aplicação do método da minimização da energia de Gibbs no cálculo de equilíbrio químico e de fases em sistemas eletrolíticos / Application method of the Gibbs energy minimization to calculation of phase and chemical equilibrium in electrolyte systems
In several industrial applications are used mixtures containing different solutes, often these solutes are non-volatile, such as electrolytes. The phase and chemical equilibrium in these processes occur in the various unit operations. The stages of production, as well as the separation and purification steps are critical to product quality. Thus, the calcula
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/12/2011
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31. Cálculo do equilíbrio sólido-líquido e ajuste de parâmetros para modelos temodinâmicos em misturas binárias e ternárias de ácidos graxos, seus ésteres e triacilgliceróis / Solid-liquid equilibria calculation and parameters determination in thermodynamic models for binary and ternary mixtures of fatty acids, esters and triacylglycerols
O trabalho desenvolvido é de caráter teórico e computacional e tem como objetivo o estudo e aplicação de técnicas de otimização juntamente com análise de convexidade para cálculo do equilíbrio sólido-líquido, utilizando um problema de Programação Não-linear, implementado no software GAMS em conjunto com o software Microsoft Excel, aplicado a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/09/2011
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32. Adsorption isotherms and thermochemical data of FD&C Red n° 40 binding by Chitosan
Chitosan is a natural polymer that has been employed in dye adsorption. In this work, adsorption and thermodynamic data for the interaction of FD&C Red n° 40 food dye with chitosan in aqueous solutions were investigated. The equilibrium adsorption isotherms were determined by the batch method, from 298 to 338 K. Adsorption data were adjusted to five isother
Brazilian Journal of Chemical Engineering. Publicado em: 2011-06
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33. Remoção dos corantes azul brilhante, amarelo crepúsculo e amarelo tartrazina de soluções aquosas utilizando carvão ativado, terra ativada, terra diatomácea, quitina e quitosana: estudos de equilíbrio e termodinâmica
This work compared activated carbon, activated earth, diatomaceous earth, chitin and chitosan to removal acid blue 9, food yellow 3 and FD&C yellow nº 5 dyes from aqueous solutions with different pH values (2-10). In the best process condition for each dye, equilibrium studies were carried out at different temperatures (from 298 to 328 K) and Langmuir, Freu
Química Nova. Publicado em: 2011
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34. Transições de fase hádron-quark em estrelas de nêutrons
Recent advances on the field of high energy physics have enabled the study of matter under extreme conditions and, in this context, new states of matter are being discovered and speculated upon. Among these hypothetical states of matter is the one of deconfined quarks in high densities and/or temperatures. An environment with extreme densities and low temper
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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35. Análise global da estabilidade termodinâmica de misturas: um estudo com o método do conjunto gerador / Global analysis of the thermodynamic stability of mixtures: a study with the method of generating set
O cálculo do equilíbrio de fases é um problema de grande importância em processos da engenharia, como, por exemplo, na separação por destilação, em processos de extração e simulação da recuperação terciária de petróleo, entre outros. Mas para resolvê-lo é aconselhável que se estude a priori a estabilidade termodinâmica do sistema, a qual
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/12/2010
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36. Application of biowaste (waste generated in biodiesel plant) as an adsorbent for the removal of hazardous bye - methylene blue - from aqueous phase
Solid waste (SW) from a biodiesel plant has been successfully used for the removal of the hazardous cationic water soluble dye - methylene blue (MB) - from an aqueous phase. Batch adsorption studies were carried out by monitoring the pH, amount of adsorbent, initial dye concentration and contact time. Attempts have also been made to monitor the adsorption pr
Brazilian Journal of Chemical Engineering. Publicado em: 2010-06